The present invention relates to evaporative coolers, of the type known as "swamp coolers", designed to cool homes and other buildings through an evaporative cooling effect. These conventional forms of evaporative coolers employ a fan to draw air across water saturated pads or drums. The evaporating water withdraws the latent heat of vaporization from the airstream, thus cooling room air. The efficiency of evaporative coolers depends to large extent upon the temperature of the supplied water, with efficiency increasing as water temperature drops. Additionally, a lower water temperature allows lower humidity to be maintained in the room air.